Process of making sulfur dyes and their leuco bodies.



UNITED STATES PATENT oEEIoE.

MnIN, GERMANY, ASSIGNORS TO FARBWERKE VORM, MEISTER LUCIUS & BRIlNING, OF HOQHST-ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY.

Specification of Letters Patent.

Patented July 14, 1908.

Application filed March 1a, 1908. Serial No. 420,841.

To all whom it may concern:

Be it known that we, BENNO HOMOLKA, Ph. D., and ROBERT WELDE, Ph. D., chemists, citizens of the Empire of Germany, and residing at Frankfort on the Main and Hochst-on-the-Main, Germany, respectively, have invented certain new and useful Imp)rovements in the Manufacture of Sulfurized yestuffs and Their Leuco Bodies, of which the following is a specification. 4

It has been found that the ortho-thioacetophenones (phenthiol ortho methylketones) of the general formula:

-co-cH3 (wherein the hydrogen atoms of the benzene residue may be substituted fully or artially by the 'alkylor alkyloxy-residues, y halogen etc.) may be transformed into vat-dyestuffs containing sulfur by depriving them of the hydrogen. This dehydrogenation takes place in an alkaline solution by means of the atmospheric oxygen or some other oxidizingagent whereby the dyestuffs are obtained directly; or it may be effected by means of sulfur by which the leuco-bodies are first obtained, which are uickly transformed into the corresponding yestuffs by the action of the atmospheric oxygen.

The ortho-thio-acetophenones used in this process are obtained by substituting the residue SH, according to the known methods for diazo-com ounds, for the amino-group of the correspon in ortho-amino-acetophenones. The ortho-thio-acetophenones are oils which do not distil without decomposition, they are scarcely solublein water, but easily soluole in dilute alkalies and alkali sulfide. The simplest ortho-thio-acetophcnone melts in vacuum at about 124 to 126 C. Upon exposure to the air the ortho-thio-acetophenones oxidize very easily and thus yield the colorless di-thio-bodies of the general formula:

1 crystallizing out well from alcohol.

through the hot yellow solution, whereby the dyestuif produced precipitates in the form of red flakes. Some times, especially if the oxidation be slow, the formation of a blue intermediate product is observed, which on continued oxidation turns into the red dyestufi. The dyestuif is then filtered, washed with-water and may be freed from di-thiobody (a byroduct which forms in small quantities) y boiling with alcohol. The red dyestuff thus obtained is insoluble in the usual dissolvents; treated with alkaline reducing-agents, it becomes a vat-dye and will dye wool and cotton.reddish-blue shades.

In the foregoing example the atmos heric oxygen may be replaced by other oxidizingagents, such as ferricyanid of potassium, er sulfate, perborate, percarbonate etc. I owever, the oxidation by. means of the atmospheric oxygen is preferable on account of its greater cheapness and because in the artificial oxidation considerable quantities of the by-product mentioned as di-thio-body form. f

Example II: 152 parts by weight of 0rthothio-acetophenone are introduced into about 750 arts by weight of melted sodium sulfid aS+9H,O) and heated while stirring well, after addition of 64 parts by weight of sulfur, until about half of the water of crystallization has evaporated. Afterwards the melt is maintained in a reflux apparatus until no more parent material is traceable. Now, the melt contains the leuco-body and may, when dissolved in water, be directly .used for dyeing. When exposed to the air, the red dyestuff separates immediately from the aqueous solution of the melt.

Having now described our invention, what we claim is:-

The process for the production of dyestuffs containing sulfur which consists in treating ortho-thio-acetophenones (phenthiol orthm methylketones) in alkaline solutions with dehydrogenating agents, whereby, when sulfur is used as such an agent, at first the leucobodies are obtained.

In testimony, that we claim the foregoing as our invention, we have signed our names in presence of two subscribing witnesses. BENNO HOMOLKA. I ROBERT WELDE. Witnesses:

JEAN GRUND, CARL GRUND. 

